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Transcript
Cell Membrane Outside of cell Proteins Carbohydrate chains Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer Membrane structure Semi-Permeable Selectively Permeable Amphipathic~ hydrophobic & hydrophilic regions Fluid Mosaic Model The Structure of the Cell Membrane Outside of cell Proteins Carbohydrate chains Cell membrane Inside Protein of cell (cytoplasm) channel Lipid bilayer Membrane structure Phospholipids~ membrane fluidity Cholesterol~ membrane stabilization and fluidity “Mosaic” Structure~ Integral proteins~ transmembrane proteins Peripheral proteins~ surface of membrane proteins Membrane carbohydrates ~ cell to cell recognition; Random movement results in Solution – mixture of solute and solvent Solute – substance being dissolved Solvent – substance dissolving solute Living Things (Universal Solvent)-Water Membrane traffic Passive transport~ diffusion of a substance across a biological membrane (NO ENERGY) [] = concentration Diffusion~ the overall movement of particles from a region of high [] to an area of low [] Osmosis~ the diffusion of water across a selectively permeable membrane Results of Diffusion Dynamic equilibrium Once diffusion has evenly distributed the solute throughout the solvent; movement of particles continues with no change in [] Homeostasis Preservation of equilibrium Diffusion depends on [] gradient [] gradient: the difference in [] of a substance across space Diffusion is said to move down a [] gradient Diffusion continues until there is NO [] gradient Ex: O2 diffuses into oxygen depleted blood Diffusion molecules like WATER, OXYGEN, AND CARBON DIOXIDE can move in and out freely. Small Large molecules like PROTEINS AND CARBOHYDRATES CANNOT Charged IONS CANNOT QuickTime™ and a Cinepak decompressor are needed to see this picture. Osmosis Osmosis~ the diffusion of water across a selectively permeable membrane Questions Osmosis is the diffusion of _______ across a cell membrane. Osmosis and Diffusion are both types of __________ transport. Passive transport does or does not require energy? Small molecules can not move across freely. T or F Large molecules can move freely. T or F Three Different Types of Solutions Isotonic Solution Hypotonic Solution Hypertonic Solution Isotonic Solution The solute outside the cell is equal in concentration to the solute in the cell. The cell retains its shape. water moves equally in both directions Hypotonic Solutions Solution outside the blood cell contains a lower [] of solute than inside of the cell. Water will diffuse in. cell will lyse (burst). Animal cells - cytolysis. Plant cells do not burst- turgur pressure— grocers use this idea Cells in a Hypotonic Solution Hypertonic Solutions The solution outside the cell has a higher [] of solute than inside of the cell. Water will diffuse out of the cell, causing the cell to shrink or crenate Why should you not salt meat before cooking? CRENATION PLASMOLYSIS Cells in a Hypertonic Solution In what type of solution would these cells be found? Water balance Summary Osmoregulation~ control of water balance Hypertonic~ higher concentration of solutes Hypotonic~ lower concentration of solutes Isotonic~ equal concentrations of solutes Water balance Summary Osmoregulation~ control in cells with cell walls: Turgid (very firm) - Hypo Flaccid (limp) - Iso Plasmolysis~ Hyper plasma membrane pulls away from cell wall Plasmolysis QuickTime™ and a Cinepak decompressor QuickTime™ and a are needed toCinepak see thisdecompressor picture. are needed to see this picture. Turgidity Other Ways to Transport Molecules Across the Plasma Membrane Selective Transport Review Covered Passive Transport Osmosis Does it require energy? NO!!! Diffusion Does it require energy? NO!!! Osmosis What is osmosis? WATER The movement of ___________ across the cell membrane. Is it the movement of any other substance? NO!!!! Diffusion Mixing of two substances by the random motion of molecules. Molecules move from a region of high concentration to an area of low concentration. How do other molecules cross the cell membrane??? Selective Transport Facilitated Diffusion (Another Passive Transport) Active Transport • Protein Pumps • Endocytosis • Exocytosis Selective Transport There are two types of selective transport Facilitated Diffusion • DOES NOT require the use of energy Active Transport • DOES require the use of energy Facilitated Diffusion Glucose molecules High Concentration Cell Membrane Low Concentration Protein channel Facilitated Diffusion Does facilitated diffusion require the use of energy? NO!!!! It uses a [] gradient to transport molecules The molecules move from an area of high [] to an area of low [] Most SUGAR molecules pass across the cell membrane by this method of transport Carrier Proteins Carry Molecules Across the Membrane Good Example - transport of Glucose into the Cell Active Transport Does active transport require the use of energy? YES!!! It uses ATP Transports against the [] gradient. Low to High [] Sodium Potassium Pump, Endocytosis and Exocytosis Active Transport Molecule to be carried Energy Molecule being carried Active Transport: Sodium Potassium Pump Move Sodium out of the cell Move Potassium into the cell Uses energy (ATP) Causes the protein to change shape Move against a [] gradient Sodium Potassium Pump Bulk Transport-Active Endocytosis Pinocytosis Phagocytosis Exocytosis Endocytosis During ENDOCYTOSIS the Cell Membrane folds into a POUCH (Vescicle) that Encloses the Particles. Two Types of Endocytosis: Pinocytosis and Phagocytosis PINOCYTOSIS ---"CELL DRINKING“—Small Particles PHAGOCYTOSIS---- "CELL EATING“-Large Particles Treatments Exocytosis EXOCYTOSIS is the opposite OR reverse of ENDOCYTOSIS. EXOCYTOSIS, wastes and cell products leave the cell. Specialized Transport Summary Transport proteins Facilitated diffusion~ passage of molecules and ions with transport proteins across a membrane down the [] gradient Active transport~ movement of a substance against its [] gradient with the help of cellular energy Elaborate Cell Membrane Bubbles Cellular Transport Flow Chart